Find & Scan Wireless Networks from the Command Line in Mac OS X

Reindexing Spotlight from the Command Line

Reindexing Spotlight from the command line is done with the mdutil tool, first launch Terminal and then type:

sudo mdutil -E /

This will reindex every mounted volume on the Mac, including hard drives, disk images, external drives, etc. Specific drives can be chosen by pointing to them in /Volumes/, to only rebuild the primary Macintosh HD:

sudo mdutil -E /Volumes/Macintosh\ HD/

To reindex an external drive named “External” the command would be:

sudo mdutil -E /Volumes/External/

Use of the mdutil command will spin up mds and mdworker processes as Spotlight goes to work.

Individually Reindexing Selected Files
In rare cases, Spotlight can miss a file during index, so rather than reindex an entire drive you can also manually add an individual file to the search index with the mdimport command:

Convert a DMG file to ISO

Convert an ISO file to DMG format

Set a Zip Password in Mac OS X

zip -e archivename.zip filetoprotect.txt
unzip filename.zip

How to Remove Apps from Launchpad in Mac OS X

Using Launchpad — Mac App Store apps only
Hold down the Option key, and once the icons start jiggling click the “X” shown in the corner of icons that you want to delete. This removes the app from Launchpad, and does not uninstall them, but this is limited to apps installed from the Mac App Store. If you want to remove an app not installed through the Mac App Store, you have to use the method below:

Using the Terminal — removes any application
Launch the Terminal and enter the following command, replacing “APPNAME” with the name of the application you want to remove from Launchpad:

删除菜单栏的图标

How to Remove Icons from the Menu Bar in Mac OS X

holding down the Command key and dragging items out of the menu

快速使用Google搜索

只要是Cocoa程序, 你都可以选择一些文字然后按Shift+Command+L快速以Google搜索。（在Safari中试试看）

quickly access System Preferences

If you want to quickly access the Mac OS X System Preferences,
you can do so by holding down the Option key and then hitting various function keys.
Option+Brightness pulls up the Display preference pane, Option+Expose brings up the Expose preferences,
Option+Volume controls bring up the Sound preferences, and so on.